Using this co-electrodeposition method, we successfully prepared a Cu-Ni alloy film at a low temperature. The results of this study showed that when Cu-Ni film is co-deposited at - 1.3 V (vs. Ag/AgCl) in a solution with a composition ratio of Ni to Cu ions of 90:10, the atomic percentage of Cu to Ni necessary to form the Cu-Ni alloy is approximately one. Electroplated for 20 min, the thickness of the Cu-Ni film grows to around 10 mu m, and the resistance is approximately 103 m omega. In this work, the samples were annealed at 700, 800, and 900 degrees C for 30 min, respectively. The resistance increased gradually with increases in the annealing temperature because of the increasing entropy of the Cu-Ni alloy. On the contrary, the TCR decreased gradually with increases in the annealing temperature. The sample annealed at 900 degrees C exhibited a single crystal FCC Cu-Ni alloy with a lattice constant of 3.62 angstrom, corresponding to a very low TCR of around 50 ppm/ degrees C. Graphic